I couldn't think of a good subject header but here's what I'm wondering about ...

...things you routinely make/cook that are specifically made to be used as ingredients in other cooking - you make them yourself and always keep them on hand. b/c they're so useful and versatile for the cooking you do. In your mind. they're as basic to your cooking as salt - they're something your kitchen should never be without. Even if its possible to buy it, you personally would never do so - you always make it yourself.